1. Field of the Invention
The present invention generally relates to a positioning platform and a machine tool, and more particularly, to a toggle-type positioning platform and a toggle-type machine tool.
2. Description of Related Art
With recent advancement in technology, current industry products have developed to be more miniaturized. Accordingly, the micro/meso-scale manufacturing technology is the key point in the oncoming fabrication technology. The micro/meso-scale manufacturing technology may be applied to products of national defence, aviation, electronics, optics, communications, medical treatment and so on. Particularly, it may be applied to the fabrication of micro optical components of high-speed signal transmission, cars, micro-actuators and micro-sensors in medical use, micro-nozzles of high-temperature jet engines, micro fuel cells, micro holes of optical fibers, photolithography technology and so on.
In applications in industry, precise machining is based on high precision positioning technology. Therefore, how to enhance precise positioning is an important index in promotion of industry. The difficulties of the precise positioning technology resulted from too many uncertain factors. Generally, the factors, which are not concerned in large-scale positioning, should be concerned in micro/nano scale positioning.
The wet etching, plasma etching, LIGA process, electron beam, ion beams and so on are used in micro-scaled fabrication process, thus resulting in the development of micro-electro mechanical system (MEMS). Generally speaking, MEMS technology is applied in the fabrication of 2˜2.5D geometry, and the relative precision of fabrication is limited to 10−1˜10−2 millimeter. However, for many 3-D miniaturized products having requirements of higher precision and complex shape, the MEMS technology is not able to meet the requirements. Besides, another bottleneck of the MEMS technology is that it can not be applied to metallic material or other diversified materials. Further, scanning tunneling microscope (STM) or atomic force microscope need to be used in nano-scaled fabrication, but the operation speed is lower and the technique is not mature.
Currently, machine tools of multi-axles are serial connected mechanism. This serial connected mechanism, which is similar to cantilever beams, has a larger working area, but it may deform or have displacement due to external loading or its weight. Therefore, only the conventional servo system of serial connected mechanism of higher precision may achieve the precision of sub-micron or even nano-meter scaled. However, the requirements of the related control technique are very strict, and the cost of the whole equipment is effectively increased. Besides, machines features the piezoelectric actuators also have the problems of smaller stroke and hysteresis.